Updated 12 pm, Thursday, Aug. 16
Open, closed, open again. West Tisbury health agent John Powers said Uncle Seth’s Pond off Lambert’s Cove Road is open to swimming.
On Wednesday, August 15, Mr. Powers closed the pond less than one week after he reopened it to swimming on August 9 following a six-week closure due to high levels of bacteria.
On Monday, West Tisbury health agent John Powers said he was cautiously optimistic that the pond would remain open despite runoff from recent heavy rains. He said the wind has picked up, which helps to oxygenate the water.
His optimism was short-lived, however. In an email to The Times Wednesday morning, Mr. Powers said the pond was closed after water samples taken Monday revealed high levels of bacteria. He said the pond would be resampled Wednesday.
Over state levels
Water samples tested at the beginning of July indicated that bacteria levels were higher than state regulations allowed, so the pond was ordered closed to swimmers.
On July 9, tests indicated 216 colony forming units per 100 milliliters (cfu/100ml) of enteroccoci bacteria in the water. State regulators require freshwater ponds closed if the bacteria counts exceed 61 cfu/100ml.
Beach closures have become regular occurrences across the Island in recent summers.
Last week, Oak Bluffs health officials closed Medeiros Cove, near the Sailing Camp Park on Lagoon Pond, to swimming, after water tests showed more than the allowed amount of harmful bacteria in the water. It has since been reopened.
Water samples taken at Medeiros Cove on August 6, showed 1,401 colony forming units per 100 milliliters (cfu/100ml) of enterococci bacteria. State regulators require saltwater beaches closed if the level exceeds 104 cfu/100ml.
The pond at Lucy Vincent Beach in Chilmark remains closed this week. The oceanfront beach remains open.
Water samples taken on Monday, August 2, from the pond at Lucy Vincent Beach show enterococci bacteria at 2,014 cfu/100ml, nearly 20 times the amount considered safe by state regulators. Water taken from the ocean off Lucy Vincent Beach, and from the ocean off the Chilmark Pond Preserve, sites on either side of the pond, tested below allowable limits.
The Bureau of Environmental Health (BEH) posts beach water quality information on the Massachusetts Public Health Department website.
According to the Massachusetts Department of Environmental Protection (DEP), enterococci bacteria are an indicator organism that may mean water is contaminated by fecal coliform bacteria.
High levels of enterococcus can cause skin irritation, vomiting, or diarrhea.
Enterococci are a group of bacterial species within the streptococcus genus, some of which (e.g. streptococcus faecalis) are typically found in human and animal intestines and are therefore present in sewage. These tests are also referred to as indicator organisms.